The labeling of product containers, such as bottles, can be done by various methods. Early methods involved either printing information directly onto the container or alternately printing the information on a label which was then adhesively bonded to the container.
A more recent labeling method involves the application of a tubular, flexible label to the bottle. Typically, the label is preprinted with the product's name and product information and the label is then pulled over the container either manually or by machine.
The use of tubular, flexible labels have become a common way of labeling plastic, "2 liter" bottles which are popular containers for soft drinks. In general, these plastic containers are replacing glass bottles and metal cans more and more each year. The labeling of these types of containers can be time consuming and add significant cost to the product package.
Apparatus and methods for automatically placing tubular labels on product containers have been suggested. In U.S. Pat. No. 4,412,876 owned by the present assignee, a relatively high speed label applying machine is disclosed. The labeling apparatus and label applying method described in this patent have become commercially successful and are use by soft drink bottling companies, among others.
Bottles however, continuously strive to reduce operating costs. Typically, the labor costs are reduced by increasing the production speeds of the bottling and the label applying machinery. The material cost is reduced by reducing material thickness of the label itself.
It was found that the labeling machine described in the above referenced patent could reliably apply labels at the rate of approximately sixty bottles per minute. It is believed that operating the machine at much higher speeds would result in inconsistent or unreliable operation. Accordingly while the described machine is belived to have had the higher rate of label application that has been achieved commercially it is unable to mmet the bottlers' desires for even greater throughout.
It must be remembered that the labels themselves must withstand the rigors of the label applying process. By way of summary, the labels are usually supplied in the form of a continuous web. The individual labels are defined by longitudinally spaced, transverse perforations. The web is fed over a mandrel positioned above the bottle to be labeled. A gripper assembly grips the bottom of the label and pulls it downwardly over the bottle. At a predetermined position, the web is braked to prevent further movement thus causing the label held by the gripper assembly to sever itself from the remainder of the supply.
As the operating speed of the machine is increased it should be apparent that the forces applied to the web and the label being applied can be significant. As the material thickness of the web is descreased, the risk of damage to the label itself increases. Thus, it is not practical to simply increase the overall speed of the machine to increase the machine throughput. It is believed that the labels could not withstand the added stress or alternatively if the labels were made strong enough to withstand the forces they would be excessively heavy and therefore too costly.
The machine disclosed in U.S. Pat. No. 4,412,876 included a labeling assembly that was reciprocally actuated through a labeling cycle by a harmonic crank mechanism rotated by a drive motor. The bottles to be labeled were fed into the labeling machine by a separate drive arrangement including a clutch and drive motor that were energized to actuate an L-shaped pusher assembly for advancing the bottles. Although these mechanical arrangements operate satisfactorily it is believed that they could not reliably accommodate the higher throughput speeds desired by the bottling industry.